Pressurized tank sprayer having lid seal

BACKGROUND

0001This invention relates to the field of pressurized tank sprayers used for dispensing a fluid from a tank.

0002Pressurized tank sprayers are common tools in households throughout the world. These tank sprayers are typically used by individuals to disperse chemicals for lawn care, pest control, or other residential concerns.

0003Pressurized tank sprayers typically include a tank for holding chemicals and a lid that seals the tank air-tight. A hand pump is generally incorporated on the apparatus for introducing air into the sealed tank. Also, a hose is provided for channeling chemicals within the tank to a nozzle attached to the end of the hose. The user operates the hand pump to force air into the sealed tank, thereby increasing the pressure in the tank. The increased pressure in the tank forces the chemicals or other liquid in the tank through the hose and out the nozzle when the nozzle is operated.

0004A number of potential problems exist with the design of typical tank sprayers. First, if the tank is not adequately sealed, it will not retain pressure and will not be able to force liquid through the hose and out the nozzle. Therefore, a good seal between the lid and tank is required. O-ring seals are often used to provide the seal between the lid and the tank in pressurized tank sprayers. A significant amount of force is typically required to adequately compress the O-ring and establish a seal in these sprayers. Unfortunately, many individuals are not strong enough to compress the lid to the tank in a manner that provides a good O-ring seal. Accordingly, it would be desirable to provide a pressurized tank sprayer requiring less force to properly seal the lid to the tank.

0005Another problem with previous pressurized tank sprayers is that a user of the sprayer may fail to open the pressure relief valve and relieve the pressure from the tank before attempting to remove the lid from the tank. When the user forgets to properly relieve the increased pressure in the tank before attempting to remove the lid, the pressure within the tank may cause the lid to become forcibly detached from the tank during such removal attempt. Therefore, it would be desirable to provide a pressurized tank sprayer having a safety feature that automatically relieves excess pressure within a tank when a user is attempting to remove the lid from the pressurized tank.

SUMMARY

0006A pressurized tank sprayer with annular seal comprises a tank, a removable lid and an annular seal. The tank includes an interior surface and an exterior surface. A mouth is formed in the tank and provides communication between the interior and the exterior of the tank. The tank further includes a neck portion that leads to and defines the mouth. The removable lid is secured to the tank and covers the mouth. The removable lid includes a top with a depending skirt. The removable lid also includes an annular groove designed to receive the annular seal.

0007The annular seal is disposed between the tank and the lid when the lid is positioned upon the tank. The annular seal includes a collar that is retained by the annular groove on the lid. The annular seal also includes an annular sealing surface and an interior concave surface. The annular sealing surface and the interior surface of the lid skirt define an annular channel that receives the neck portion of the tank when the removable lid is secured upon the tank. In particular, when the neck portion of the tank is positioned in the annular channel, an exterior surface of the neck portion contacts the interior surface of the skirt and an interior surface of the neck portion contacts the annular sealing surface of the annular seal. The interior concave surface of the annular seal is exposed to the interior of the tank when the lid is secured to the tank.

0008In one embodiment, the exterior surface of the neck portion of the tank includes a first plurality of threads, and the interior surface of the lid skirt includes a second plurality of threads. The first plurality of threads is operable to move in rotatable engagement relative to the second plurality of threads. Also, the first plurality of threads is operable to move in rotatable disengagement relative to the second plurality of threads. The first plurality of threads and the second plurality of threads include means for permitting an axial shift of the first plurality of threads relative to the second plurality of threads in response to an increased pressure within the tank during rotatable disengagement of the first plurality of threads relative to the second plurality of threads. This axial shift permits the increased pressure to be released from the tank without disengagement of the first plurality of threads from the second plurality of threads.

BRIEF DESCRIPTION OF THE DRAWINGS

0009<figref idref="DRAWINGS">FIG. 1</figref> is a top perspective view of a pressurized tank sprayer with an annular seal that incorporates the features of the present invention therein, and showing a tank and lid together, with a cutaway view of a tank interior and a cutaway view of the lid;

0010<figref idref="DRAWINGS">FIG. 2</figref> is a top perspective view of the tank of the pressurized tank sprayer of <figref idref="DRAWINGS">FIG. 1</figref>;

0011<figref idref="DRAWINGS">FIG. 3</figref> is a perspective exploded assembly view of the lid of the pressurized tank sprayer of <figref idref="DRAWINGS">FIG. 1</figref>;

0012<figref idref="DRAWINGS">FIG. 4</figref> is a perspective view of the lid of the pressurized tank sprayer of <figref idref="DRAWINGS">FIG. 1</figref>;

0013<figref idref="DRAWINGS">FIG. 5</figref> is a side perspective view of the tank of the pressurized tank sprayer of <figref idref="DRAWINGS">FIG. 1</figref> showing a cutaway view of the threads on the tank and the lid;

0014<figref idref="DRAWINGS">FIG. 6</figref> is another side perspective view of the pressurized tank sprayer of <figref idref="DRAWINGS">FIG. 1</figref> showing a cutaway of the lid as it is removed from the tank and showing an annular sealing ring seated in the lid;

0015<figref idref="DRAWINGS">FIG. 7</figref> shows an enlarged perspective view of the annular sealing ring of <figref idref="DRAWINGS">FIG. 6</figref>;

0016<figref idref="DRAWINGS">FIG. 8</figref> shows a top plan view of the annular sealing ring of <figref idref="DRAWINGS">FIG. 7</figref>;

0017<figref idref="DRAWINGS">FIG. 9</figref> shows a cross-sectional view of the annular sealing ring along line IX-IX of <figref idref="DRAWINGS">FIG. 8</figref>;

0018<figref idref="DRAWINGS">FIG. 10</figref> shows a cross-sectional view of the annular sealing ring of <figref idref="DRAWINGS">FIG. 7</figref> seated within the lid and in contact with the tank;

0019<figref idref="DRAWINGS">FIG. 11A</figref> shows a linear projection of threads on the lid and tank of the pressurized tank sprayer of <figref idref="DRAWINGS">FIG. 1</figref> just before the lid is released from the tank; and

0020<figref idref="DRAWINGS">FIG. 11B</figref> shows a linear projection of the threads of <figref idref="DRAWINGS">FIG. 11A</figref> with the threads of the lid axially displaced from the threads of the tank.

DESCRIPTION

0021With reference to <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, a pressurized tank sprayer <b>12</b> is shown. The pressurized tank sprayer includes a base tank <b>14</b> and a lid <b>16</b> positioned upon the tank. A pump <b>18</b> is formed in the lid <b>16</b> along with a pressure release valve <b>20</b>. An outlet port <b>22</b> is also positioned on the lid <b>16</b>. A tube <b>24</b> extends between the outlet port and the bottom of the tank <b>14</b>. A hose <b>26</b> and nozzle <b>28</b> (see <figref idref="DRAWINGS">FIG. 3</figref>) are attached to the exterior of the outlet port <b>22</b>. The pump <b>18</b> is used to pump air into the tank <b>14</b>, thereby increasing the pressure in the tank. When the nozzle is actuated, the pressure in the tank <b>14</b> forces liquid contents of the tank through the tube <b>24</b>, past the outlet port <b>22</b>, and through the hose <b>26</b> and nozzle <b>28</b>.

0022The tank <b>14</b> includes an exterior surface <b>30</b> and an interior surface <b>32</b>. The tank is designed to hold liquid to be sprayed from the tank. The tank interior surface <b>32</b> defines a chamber <b>34</b> having a volume for holding liquid. The tank includes a lower body portion <b>36</b> and a neck <b>38</b>. The neck <b>38</b> is generally tapered or otherwise smaller in diameter than the lower body portion <b>36</b> of the tank. However, one of ordinary skill in the art will recognize that the neck <b>38</b> may have a diameter equal to the lower body portion <b>36</b>, or may be flared with a diameter greater than the lower body portion. A plurality of threads <b>50</b> are disposed upon and spiral around the neck <b>38</b>. The top of the neck <b>38</b> leads to a top rim <b>40</b>. The top rim <b>40</b> defines a mouth <b>42</b>. The mouth <b>42</b> provides an opening between the interior of the tank and the exterior of the tank. This opening is used for communication of liquids into or out of the tank chamber <b>34</b>. The tank is generally comprised of a lightweight material such as plastic. However, the tank may also be comprised of any number of other materials suitable for holding liquid, such as glass or metal.

0023A side carry handle <b>44</b> may be included on the tank, as is shown in <figref idref="DRAWINGS">FIG. 1</figref>. The side carry handle <b>44</b> may be used to stabilize the tank when the lid is being attached to or removed from the tank. In addition, the side carry handle provides a convenient location from which the user may carry the tank and/or manipulate the tank during cleaning.

0024With reference to <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, the lid <b>16</b> is generally formed of a plastic material and includes a top <b>60</b> with a depending annular skirt <b>62</b>. The top <b>60</b> of the lid includes a pressure relief port <b>64</b>, a pump opening <b>66</b> and a fluid outlet port <b>68</b>. The top of the lid <b>60</b>, skirt <b>62</b>, pressure relief port <b>64</b>, pump opening <b>66</b> and fluid outlet port <b>68</b> are all molded as a single integral unit.

0025The pressure relief port <b>64</b> is designed and dimensioned to receive a pressure relief valve <b>70</b>. The pressure relief valve includes a lever <b>72</b> operable to open and close the pressure relief valve <b>70</b>. The lever pivots 180° about a pivot point <b>74</b> between an open position and a closed position. When the lid <b>16</b> is secured to the tank <b>14</b> and the lever is in the open position, the pressure relief valve <b>70</b> is open. With the pressure relief valve open, a passage is provided allowing pressurized air/gas within the tank to escape the tank through the pressure relief valve <b>70</b>. On the other hand, when the lever <b>72</b> is in the closed position, the pressure relief valve <b>70</b> is closed. With the pressure relief valve <b>70</b> closed, the passage through the pressure relief valve <b>70</b> is blocked, thereby preventing pressurized air/gas within the tank from escaping the tank though the pressure relief valve.

0026The pump opening <b>66</b> in the lid <b>16</b> is designed and dimensioned to receive a pump plunger <b>78</b> and pump cap <b>80</b>. The pump opening <b>66</b> feeds into an elongated pump cylinder <b>76</b> integrally formed with the lid <b>16</b>. The pump cylinder <b>76</b> extends downward into the interior of the tank <b>14</b> when the lid <b>16</b> is placed on the tank. A plurality of holes <b>86</b> are formed at the bottom of the pump cylinder <b>76</b>. The cap <b>80</b> fits over the pump opening <b>66</b> in the lid and is fixed to the lid to secure the pump plunger <b>78</b> on the lid. The pump plunger <b>78</b> slideably engages the cap <b>80</b>, allowing the plunger <b>78</b> to move up and down with respect to the lid <b>16</b> and the cap <b>80</b>. A piston <b>82</b> is attached to the bottom end of the plunger <b>78</b> and is retained within the cylinder <b>76</b>. A handle <b>84</b> is attached to the top end of the plunger. The handle allows manual operation of the pump. In particular, upward movement of the handle <b>84</b> moves the plunger <b>78</b> and attached piston <b>82</b> upward within the cylinder <b>76</b>. As the piston <b>82</b> is moved upward, a valve (not shown) positioned upon the piston allows air to rush into the cylinder on the bottom side of the piston. Thereafter, downward movement of the handle forces the plunger and attached piston downward in the cylinder. When the piston moves downward, the valve is closed, forcing air out of the holes <b>86</b> in the bottom of the cylinder. In this manner, air may be forced into the tank <b>14</b> in order to pressurize the tank.

0027With continued reference to <figref idref="DRAWINGS">FIG. 3</figref>, the pump handle <b>84</b> includes two hooks <b>94</b> that depend from the bottom of the handle. Each hook <b>94</b> includes a downward extending portion <b>96</b> and a cross member <b>98</b>. Two shelves <b>46</b> are formed on the top <b>60</b> exterior surface of the lid <b>16</b>. Each shelf <b>46</b> provides a contact surface designed and dimensioned to receive the hooks <b>94</b> on the pump handle <b>84</b> such that the cross member <b>98</b> of each hook can be positioned under the shelf. Also, each shelf <b>46</b> includes a side flange <b>48</b> that depends downward from the shelf <b>46</b>. A spring (not shown) is provided in bottom of the pump cylinder <b>76</b>. The spring is designed to contact the piston <b>82</b> when it reaches the bottom portion of the cylinder <b>76</b>, thereby preventing the piston from resting on the bottom of the cylinder when the piston is fully depressed in the cylinder. This spring also biases the piston and pump plunger <b>78</b> slightly upward when the piston is near the bottom of the cylinder. In particular, if the handle <b>84</b> is used to push the piston <b>82</b> to the bottom of the cylinder <b>76</b>, and the handle is then released, the spring will press against the piston and bias the piston and plunger slightly upward. Together, the spring, hooks and shelf provide a stationary rest for the handle. In order to place the handle in the stationary rest, the user first moves the handle <b>84</b> downward such that the piston <b>82</b> compresses the spring in the cylinder <b>76</b>. Next, the handle <b>84</b> is rotated so the cross members <b>98</b> of the hooks <b>94</b> are positioned under the shelves <b>46</b>. Finally, the user releases the handle <b>84</b>, allowing the spring to move the piston <b>82</b>, plunger <b>78</b> and connected handle <b>84</b> slightly upward so the cross members <b>98</b> on the hooks <b>94</b> contact the lower surface of the shelf <b>46</b>. The flanges <b>48</b> retain the hooks <b>94</b> and connected handle <b>84</b> in place under the shelf <b>46</b> until the user forces the handle downward again and rotates the cross members <b>98</b> of the hooks under the shelf and depending flanges, thereby freeing the handle for pumping action.

0028The fluid outlet port <b>68</b> is also positioned on the top of the lid <b>16</b> and provides an opening in the lid. The tube <b>24</b> extends through the bottom side of the fluid outlet port <b>68</b>. The cylinder <b>76</b> includes an exterior track <b>88</b> for receiving the tube and holding it in place within the tank. A screen filter <b>90</b> is positioned at the bottom of the tube <b>24</b> for blocking solid particles from passing into the tube that may be large enough to clog or otherwise damage the nozzle <b>28</b>. One end of the hose <b>26</b> is attached to the nozzle <b>28</b>. The opposite end of the hose is attached to the top of the exterior surface of the fluid outlet port <b>68</b>. A clamp <b>92</b> is used to secure the hose <b>26</b> to the fluid outlet port <b>68</b>.

0029The skirt <b>62</b> of the lid <b>16</b> depends from the top <b>60</b> of the lid in an annular fashion. The skirt includes an interior surface <b>101</b> and an exterior surface <b>103</b>. The interior surface <b>101</b> of the skirt defines a portion of an interior lid surface <b>102</b>, and the exterior surface <b>103</b> of the skirt defines a portion of an exterior lid surface <b>104</b>. The exterior lid surface <b>104</b> includes handles <b>108</b> as well as a plurality of gripping bars <b>106</b>. The handles <b>108</b> may be used to carry the pressurized tank sprayer <b>12</b>, and may also be used along with the gripping bars <b>106</b> when twisting the lid <b>16</b> on or off of the tank <b>14</b>.

0030The interior lid surface <b>102</b> is best viewed with respect to <figref idref="DRAWINGS">FIG. 4</figref>. As mentioned previously, the cylinder <b>76</b> extends from the center of the lid interior. A plurality of ribs <b>112</b> extend from the cylinder <b>76</b> toward the skirt <b>62</b>, but do not extend to the skirt. Instead, the ribs <b>112</b> extend to an annular wall <b>114</b> which is concentric with the cylinder. The annular wall <b>114</b> is also concentric with the skirt <b>62</b>. The annular wall depends from the top <b>60</b> of the lid, but does not extend downward as far as the skirt <b>62</b>. A plurality of skirt threads <b>110</b> spiral around the interior surface of the skirt. The plurality of skirt threads are designed to engage the plurality of neck threads on the tank, thereby securing the lid to the tank.

0031With reference to <figref idref="DRAWINGS">FIGS. 6-9</figref>, an annular seal <b>120</b> is retained upon the lid <b>16</b>. The seal <b>120</b> is retained upon the lid <b>16</b> in a seal seat <b>122</b> which is formed on the interior surface <b>102</b> of the lid. The annular seal <b>120</b> is generally ring-shaped, as shown in <figref idref="DRAWINGS">FIG. 8</figref>. The annular seal is made of a resilient material, such as a soft rubber material, and is formed as a single integral piece. As shown in <figref idref="DRAWINGS">FIGS. 6</figref>, <b>7</b>, <b>9</b>, and <b>10</b>, the seal <b>120</b> has a generally “h” shaped cross section. The seal <b>120</b> includes an interior lip <b>126</b> and an exterior lip <b>128</b> joined by a curved upper body portion <b>130</b>. An annular collar <b>124</b> is formed adjacent to the interior lip <b>126</b> and the upper body portion <b>130</b>. The annular collar extends upward above the interior lip <b>126</b> and the upper body portion <b>130</b>. The top of the annular collar has a generally rectangular cross-section. A concave interior surface <b>132</b> is defined by the interior lip <b>126</b>, exterior lip <b>128</b> and upper body portion <b>130</b>. The concave interior surface is U-shaped, and forms an annular trench <b>138</b> within the seal <b>120</b>. A flat seating surface <b>134</b> is defined by the interior lip <b>126</b> and the top collar <b>124</b>. A convex exterior surface <b>136</b> is defined by the exterior lip <b>128</b> and the upper body portion <b>130</b>. As explained in further detail below, the convex exterior surface <b>136</b> provides an annular sealing surface <b>136</b> that contacts the tank <b>14</b>. As shown in <figref idref="DRAWINGS">FIG. 9</figref>, the lower portion of the annular sealing surface <b>136</b> that forms the exterior lip <b>128</b> includes a flat portion <b>138</b>.

0032As shown in <figref idref="DRAWINGS">FIG. 10</figref>, it can be seen that the top portion of the lid <b>16</b> includes a ramp structure <b>200</b> that projects into the space defined between the annular wall <b>114</b> and the skirt <b>62</b> so as to define a ramped seal seat surface <b>202</b>. When (i) the curved upper body portion <b>130</b> is positioned in contact with the ramped seal seat surface <b>202</b>, and (ii) the interior lip <b>126</b> is positioned in contact with the annular wall <b>114</b>, it can be seen that the seal <b>120</b> extends beyond the ramped seal seat surface <b>202</b> so as to position the exterior lip <b>128</b> in contact with the neck portion of the tank <b>14</b> at a seal location <b>203</b>. As also can be seen in <figref idref="DRAWINGS">FIG. 10</figref>, a first gap <b>204</b> is defined between the exterior lip <b>128</b> and the neck portion of the tank <b>14</b> on a first side of the seal location <b>203</b>, while a second gap <b>206</b> is defined between the exterior lip <b>128</b> and the neck portion on a second opposite side of the seal location <b>203</b>.

0033With reference to <figref idref="DRAWINGS">FIGS. 7 and 10</figref>, the seal seat <b>122</b> provided by the lid <b>16</b> includes an annular groove <b>140</b> formed in the lid around the annular wall <b>114</b>. The annular groove <b>140</b> is designed and dimensioned to snugly receive the annular collar <b>124</b> of the seal <b>120</b>. The seal seat <b>122</b> also includes a transverse support surface <b>142</b>. The transverse support surface <b>142</b> is concave and extends laterally away from the annular groove <b>140</b>. When the seal <b>120</b> is positioned in the seal seat, the seal collar <b>124</b> is snugly held within the annular groove <b>140</b> in the lid. At the same time, the flat seating surface <b>134</b> of the seal <b>120</b> is flush against the annular wall <b>114</b> in the lid. Furthermore, the curved upper portion <b>130</b> of the concave exterior surface <b>136</b> of the seal <b>120</b> is in contact with the concave transverse support surface <b>142</b>. The lower portion of the concave exterior surface <b>136</b> of the seal extends downward from the transverse support surface <b>142</b>, such that the exterior lip <b>128</b> of the seal is free to move back and forth in the radial direction. An annular channel <b>144</b> is formed between the exterior surface <b>136</b> of the seal <b>120</b> and the interior surface <b>101</b> of the skirt <b>62</b> which depends from the top <b>60</b> of the lid <b>16</b>. A channel ceiling <b>146</b> is provided by the top interior surface <b>102</b> of the lid.

0034As shown in <figref idref="DRAWINGS">FIG. 10</figref>, the annular seal <b>120</b> serves to provide a seal between the lid <b>16</b> and the tank <b>14</b>. In particular, as the lid <b>16</b> is positioned on the tank <b>14</b>, the threads on the neck of the tank rotatably engage the threads on the skirt of the lid and draw the lid downward upon the neck <b>38</b> and top rim <b>40</b> of the tank. As the threads near full engagement, the neck <b>38</b> of the tank enters the annular channel <b>144</b> formed between the seal <b>120</b> and the interior surface of the skirt <b>62</b>. When the neck <b>38</b> of the tank enters the annular channel <b>144</b>, the interior surface <b>32</b> of the neck contacts the annular sealing surface <b>136</b> of the seal <b>120</b>. As the neck <b>38</b> passes further into the annular channel <b>144</b>, the force of the neck against the annular sealing surface <b>136</b> causes the seal to slightly deform. However, relatively little force in addition to the rotational force required for thread engagement is required from the user to force the neck <b>38</b> of the tank into the annular channel <b>144</b> formed in the lid and against the annular sealing surface <b>136</b>. Because the seal <b>120</b> is resilient, the deformed annular sealing surface <b>136</b> presses against the tank and forms a seal with the tank. While the exterior lip of the seal <b>120</b> is allowed to deform and shift to form the seal, the other portions of the seal <b>120</b> remain substantially stationary in the seal seat, pressed against the annular wall <b>114</b>, annular groove <b>140</b> and transverse support surface <b>142</b>. Once the top rim <b>40</b> of the tank contacts the channel ceiling <b>146</b>, the further engagement of the neck <b>38</b> of the tank into the annular channel <b>144</b> in the lid is prohibited. However, the top rim <b>40</b> of the tank need not contact the channel ceiling <b>146</b> for proper sealing between the tank and lid to occur. For example, further engagement of the neck into the annular channel <b>144</b> may be prohibited upon full and complete engagement of the neck threads with the skirt threads.

0035With the lid <b>16</b> secured on the tank <b>14</b>, the annular seal <b>120</b> is in contact with and sealed against the tank interior surface <b>32</b>, as discussed above. Accordingly, the U-shaped interior surface <b>132</b> of the annular seal <b>120</b> is exposed to the interior of the tank along with the associated annular trench <b>138</b>. When pressure is introduced into the tank interior that is greater than the atmospheric pressure experienced on the outside of the tank, the pressure provides an outward force on the interior surface of the tank. This pressure also provides an outward force on the U-shaped interior surface <b>132</b> of the annular seal, since it is exposed to the tank interior. The outward force on the interior surface <b>132</b> of the annular presses the annular sealing surface <b>136</b> against the interior surface of the tank <b>32</b> and helps maintain the seal between the lid <b>16</b> and the tank <b>14</b> when the tank is pressurized.

0036In order to remove the lid <b>16</b> from the tank <b>12</b>, the lid is rotated relative to the tank such that the threads move in rotational disengagement. As the lid is removed, the neck <b>38</b> of the tank is moved out of the annular channel <b>144</b>. After the neck passes out of the annular channel <b>144</b>, and the seal <b>120</b> is completely disengaged from the interior surface of the neck <b>38</b>, the resilient exterior lip <b>128</b> of the seal shifts away from the annular trench <b>138</b> and returns to its equilibrium position.

0037In one alternative embodiment, the pressurized tank sprayer includes a locking thread feature that allows excess pressure inside the tank that is greater than atmospheric pressure to escape the tank before the threads on the tank and the threads on the lid are completely disengaged. With reference to <figref idref="DRAWINGS">FIGS. 11A and 11B</figref>, a linear projection is shown of the neck threads <b>50</b> of the tank <b>14</b> partially engaged with the skirt threads <b>110</b> of the lid over approximately 180° of the annular surface of the neck and skirt. The neck threads <b>50</b> of the tank <b>14</b> are shown with cross-hatching from right to left. The skirt threads <b>110</b> are shown with cross-hatching from left to right.

0038The neck threads <b>50</b> are formed on the exterior surface of the neck of the tank, are helical in shape, and spiral downward around the neck. Each neck thread includes a starting portion <b>158</b> at one end of the thread nearest the mouth, and an ending portion <b>58</b> at the opposite end of the thread. Also, each neck thread includes a mouth side <b>52</b> and a bottom side <b>54</b>. A plurality of grooves <b>56</b> are formed between the neck threads such that a groove is formed between the bottom side of a thread and the mouth side of an adjacent thread. The grooves <b>56</b> expose the surface of the tank between the neck threads and provide tracks for receiving the skirt threads on the lid. The neck threads typically have a V-shaped cross-section, with the tip of the V pointing away from the tank. However, the threads may have other cross-sectional shapes, as will be readily recognized by those of skill in the art.

0039A recess <b>160</b> is formed in the starting portion <b>158</b> of each neck thread <b>50</b>. Each recess <b>160</b> has a depth that extends from the bottom side <b>54</b> of the thread toward the mouth side <b>52</b>, and exposes additional exterior surface of the neck where the thread would otherwise be. Each recess <b>160</b> separates a starting tip <b>164</b> of each neck thread from the remainder of the thread. A bridge portion <b>162</b> is positioned above each recess <b>160</b> to connect the starting tip <b>164</b> to the remainder of the thread. Thus, each neck thread <b>50</b> remains continuous from start to finish, as the bridge portion <b>162</b> spans across the recess in each thread. With continued reference to <figref idref="DRAWINGS">FIG. 11A</figref>, the length of each recess <b>160</b> is shown as l₃and the length of the starting tip <b>164</b> of each neck thread <b>50</b> is shown as l₄.

0040The skirt threads <b>110</b> are formed on the interior surface of the skirt <b>62</b>. The skirt threads <b>110</b> are helical in shape and spiral upward around the skirt interior. Each skirt thread <b>110</b> includes a starting portion <b>180</b> at one end of the thread nearest the bottom of the skirt, and an ending portion <b>182</b> at the opposite end of the thread nearer the top of the skirt. Also, each skirt thread <b>110</b> includes a top side <b>184</b> and a bottom side <b>186</b>. A plurality of grooves <b>188</b> are formed between the neck threads <b>110</b> such that a groove is formed between the bottom side <b>186</b> of one thread and the top side <b>184</b> of an adjacent thread. The grooves <b>188</b> expose the interior surface of the lid between the skirt threads and provide tracks for receiving the neck threads <b>50</b> on the tank. Like the neck threads, the skirt threads <b>110</b> typically have a V-shaped cross-section, with the tip of the V pointing inward from the annular skirt. However, the threads may have other cross-sectional shapes, as will be readily recognized by those of skill in the art.

0041A cut-out portion <b>190</b> is formed in each skirt thread <b>110</b> near the starting portion <b>180</b> of the thread. The cut out portion <b>190</b> forms a void in the path of the thread <b>110</b> and exposes the interior surface <b>101</b> of the skirt where the thread would otherwise be. The cut out portion <b>190</b> extends from the bottom side <b>186</b> of the thread <b>110</b> to the top side <b>184</b> of the thread. Each thread separates a starting tip <b>194</b> of the thread from the remainder of the thread. Because of the cut out portions <b>190</b> in the skirt threads <b>110</b>, and because no bridges span across the cut out portions <b>190</b>, the skirt threads are not continuous from start to finish. <figref idref="DRAWINGS">FIG. 11A</figref> shows that the length of each cut-out portion <b>190</b> is defined as l₂and the length of each starting tip <b>194</b> of the skirt thread <b>110</b> is defined as l₁.

0042The arrangement of the recesses <b>160</b> in the neck threads <b>50</b> and cut-out portions <b>190</b> in the skirt threads <b>110</b> provide the pressurized tank sprayer with a locking thread feature that permits and axial shift between the neck threads and the skirt threads. This axial shift allows excess pressure inside the tank that is greater than atmospheric pressure to escape the tank before the threads on the tank and the threads on the lid completely disengage. In particular, when the lid <b>16</b> is rotated in a counter-clockwise direction relative to the tank <b>14</b>, the skirt threads <b>110</b> will begin rotational disengagement from the neck threads <b>50</b> as the lid begins to remove from the tank. If pressure remains in the tank when the lid <b>16</b> is being removed from the tank <b>14</b>, the pressure in the tank will tend to force the lid away from the mouth of the tank. Accordingly, the top side <b>184</b> of the skirt threads <b>110</b> will be forced upward against the bottom sides <b>54</b> of the neck threads <b>50</b>. However, just before the skirt threads <b>110</b> disengage from the neck threads <b>50</b>, the starting portions <b>158</b> of the neck threads <b>50</b> will encounter the starting portions <b>180</b> of the skirt threads <b>110</b>. As the starting tips <b>194</b> on the starting portions <b>180</b> of the skirt threads <b>110</b> encounter the recesses <b>160</b> on the neck threads <b>50</b>, the pressure in the tank will force the starting tips <b>194</b> upward into the recesses <b>160</b>. At the same time, the cut out portions <b>190</b> on the skirt threads <b>110</b> will receive the starting tips <b>164</b> of the neck threads <b>50</b>. As the starting tips <b>194</b> on the lid engage the recesses <b>160</b> on the tank and the starting tips <b>164</b> on the tank engage the cut-out portions on the lid, the pressure in the tank causes the lid to shift axially upward and away from the tank without complete disengagement of the threads. This axial shift is represented in <figref idref="DRAWINGS">FIG. 11A</figref> by arrows <b>199</b>. The shifted position of the threads is shown in <figref idref="DRAWINGS">FIG. 11B</figref>. Although the distance of the axial shift is only as deep as the depth of the recess <b>160</b> in the neck thread <b>50</b>, this distance is sufficient to allow the pressurized air within the tank to escape from the tank. At the same time, the features on the starting portions of threads prevent the lid from being completely removed from the tank. Once the pressurized air has escaped, and the pressure within the tank returns to atmospheric pressure, the skirt threads <b>110</b> drop down from the position in <figref idref="DRAWINGS">FIG. 11B</figref> and rest in the grooves <b>56</b> of the neck. Additional counter-clockwise rotation of the lid relative to the tank causes the starting tips <b>194</b> of the skirt threads to pass by the starting tips <b>164</b> of the neck threads, and the lid is released from the tank. Accordingly, even if the user of the pressurized tank sprayer <b>12</b> fails to engage the pressure release valve <b>20</b> and release excess pressure within the tank prior to removal of the lid from the tank, any excess pressure will not cause the lid to become forcibly detached from the tank.

0043In general operation of the pressurized tank sprayer <b>12</b>, the tank is first filled with a liquid to be dispensed from the nozzle <b>28</b>. When the lid <b>16</b> is to be secured on the tank <b>14</b>, the lid is placed over the mouth of the tank and the lid is rotated in the clockwise direction. Clockwise rotation of the lid causes the starting tips <b>194</b> of the skirt threads <b>110</b> to enter the grooves <b>56</b> on the neck. As the lid is rotated, the bottom side <b>186</b> of the skirt threads typically rest on the top or mouth side <b>52</b> of the neck threads because of the downward pull of gravity. Continued clockwise rotation causes the neck threads and skirt threads to fully engage as the top rim <b>40</b> of the tank becomes seated in the annular channel <b>144</b> formed in the lid, as shown in <figref idref="DRAWINGS">FIG. 10</figref>.

0044Once the lid is secured to the tank, the annular seal <b>120</b> provides a seal between the lid and the tank. Because the tank is sealed, air is prevented from escaping from the tank. The user then operates the pump <b>18</b> to introduce additional air into the tank. The additional air introduced into the tank increases the pressure within the tank. As explained previously, as pressure increases within the tank the pressure provides a force against the concave interior surface <b>132</b> of the annular seal <b>120</b>, thereby maintaining secure contact between the annular sealing surface <b>136</b> and the skirt interior surface <b>103</b>. The increased pressure within the tank forces liquid through the tube <b>24</b> and out of the nozzle <b>28</b> when the user operates the nozzle.

0045Following use of the pressurized tank sprayer <b>12</b>, the user opens the pressure relief valve <b>20</b> to remove excess pressure from the tank. The user then rotates the lid in a counter-clockwise direction to remove the lid from the tank. However, as discussed previously, if the user fails to open the pressure relief valve before removing the lid, the locking features of the threads, including the recesses and cut-outs on the starting portions prevent the lid from becoming forcibly detached from the tank.

0046Although the present invention has been described with respect to certain preferred embodiments, it will be appreciated by those of skill in the art that other implementations and adaptations are possible. Moreover, there are advantages to individual advancements described herein that may be obtained without incorporating other aspects described above. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein.